Safety and efficacy of nivolumab in Japanese patients with malignant melanoma: An interim analysis of a postmarketing surveillance.

A postmarketing surveillance study is ongoing to evaluate nivolumab treatment for Japanese patients with malignant melanoma and accumulate data on all adverse events (AE) and efficacy. In this interim analysis, we evaluated data from approximately 100 Japanese medical institutions obtained from the nivolumab approval date in Japan (4 July 2014) through 3 July 2016. Patients were monitored during the first 12 months of treatment. Nivolumab was administrated by i.v. infusion (2 mg/kg every 3 weeks). A total of 680 and 610 patients were evaluated for safety and efficacy, respectively. The incidences of adverse drug reactions (ADR) and grade 3 or higher ADR were 53.53% and 12.35%, respectively. Predominant ADR included hypothyroidism (11.32%) and abnormal enzyme activity, such as increase of aspartate aminotransferase (7.79%), alanine aminotransferase (6.76%), alkaline phosphatase (6.18%) and γ-glutamyltransferase (5.44%). Grade 3 or higher ADR of special interest with an incidence of 1% or higher were hepatic function disorder (2.50%), colitis/diarrhea (2.06%) and infusion reaction (1.32%). No cases of encephalitis or venous thromboembolism, other AE of special interest, were observed. The estimated median overall survival was 379 days (95% confidence interval [CI], 290-not reached [NR]) in the overall population, NR (95% CI, 305-NR) for cutaneous melanoma and 340 days (95% CI, 275-NR) for mucosal melanoma. The improvement rate based on the antitumor response at the last evaluation was 22.2% (131/590 patients). No new safety concerns were raised, and serious ADR of special interest were infrequent. Nivolumab showed equivalent efficacy in patients with mucosal melanoma and those with cutaneous melanoma.